Electrical issue dash lights and idle

[Jack London]

Hello all.

I'm hoping someone has some insight into the following problem i've been having.

Initially I just had the flashing of the traction control, tyre pressure, abs and brake lights on the dash.
Sometimes it would be a brief flash sometimes it would stay on a bit longer.

At the same time there would also sometimes be a bit of a slightly wobbly idle but not always.

There has been a dashcam install and more recently I installed an android headunit.
Now when the dash lights flash it almost always turns off the screen and stops the music and then it will come back in a few seconds.

Other times when it's really going crazy it will do it repeatedly.
The lights on the dash will now have a red Handbrake light and also airbag light come on. This time they won't go away.
Indicating when this happens won't work. The other night if those lights were one and the stereo was on if I pressed the hazard light button (which in the past would clear the dash lights) it would turn off the android unit and it would come back off when I turned the hazards off.

I noticed that when I revved the car hard while accelerating it forced all the lights to reset and go off.
Also when all the lights and the airbag light is also on sometimes turning the aircon/fan on will also kill the stereo.

I've had two instances of a really bad idle. I'll add a video of one. I also noticed on two occasions I couldnt press the brake and accelerator at the same time. So I couldn't blip the throttle. As if it was in a limp or safe mode and the brake pedal was blocking out the accelerator.

I'm not that knowledgeable with battery testers but this is what I got:
Before Charging: voltage 12.03v measured 460cca on bmw original 720cca battery. Resistance 5.62m Life (SOH) 37.9% State of Charge 48%, indicated condition: replace battery

After Charging with external charger: Voltage 12.27V, measured 550cca, Resistance 4.74m, Life (SOH) 55.4%, State of Charge 65% indicated condition: great

Starting voltage reading: Min 9.4V Max 12.0V

Alternator test under load over 2.5k rpm passed fine according to the tester.

I ran the car without the MAF sensor but it didn't seem to change the normal occasionally wobbly idle and made no difference to the dash lights and cut outs.

I think it happens more when the car is at temperature. It does seem to happen when pulling away at times but its also happened when cruising along at a steady speed.

I've heard it could be the battery or something far more expensive.

I thank anyone who has read this far and anyone who might have an idea what it could be that I might be able to tackle before going to get a big bill somewhere

Idle video: https://imgur.com/EQCjfny
battery readout on idle: https://imgur.com/DXnOMjU

Cheers

 

[thecremeegg]

This may seem silly but you have checked the battery connectors are done up tight? I had all kinds of similar issues and couldn't figure it out as the terminals looked fine, turns out tightening them fixed it.
Long shot but worth a check

 

[instigata]

How old is the battery? I have had an airbag light go off once and the EPS light another time due to low battery. From what I've read on the forum, at idle you should have ~13.3V.

 

[Jack London]

This may seem silly but you have checked the battery connectors are done up tight? I had all kinds of similar issues and couldn't figure it out as the terminals looked fine, turns out tightening them fixed it.
Long shot but worth a check

battery is tight as can be!

How old is the battery? I have had an airbag light go off once and the EPS light another time due to low battery. From what I've read on the forum, at idle you should have ~13.3V.

Not sure. The battery has a date month and year which says March 2020 but can't tell if that's when installed when recharged or when due for replacement.

 

[Jack London]

This may seem silly but you have checked the battery connectors are done up tight? I had all kinds of similar issues and couldn't figure it out as the terminals looked fine, turns out tightening them fixed it.
Long shot but worth a check

battery is tight as can be!

How old is the battery? I have had an airbag light go off once and the EPS light another time due to low battery. From what I've read on the forum, at idle you should have ~13.3V.

Not sure. The battery has a date month and year which says March 2020 but can't tell if that's when installed when recharged or when due for replacement.

 

[Jack London]

I also tried unplugging each ignition coil in turn incase one of those was misfiring but they all seemed fine.

 

[Jas- USA]

Please see: https://www.bimmerfest.com/threads/when-ignition-switch-goes-bad.1365365/

 

[Jack London]

Please see: https://www.bimmerfest.com/threads/when-ignition-switch-goes-bad.1365365/

Interesting. There are some similarities going on,.though not quite the same I'll have a look for an ignition switch and add it to the things to try.

Thanks

 

[raymond.harper]

I would check the earthing cables. A good code reader is invaluable in these cases, it will detect faults you don't know you have! https://z4-forum.com/forum/viewtopic.php?t=13765

 

[Jack London]

I would check the earthing cables. A good code reader is invaluable in these cases, it will detect faults you don't know you have! https://z4-forum.com/forum/viewtopic.php?t=13765

Do you have any examples of what you deem to be a good code reader? I was looking into that software and cable because my reader doesn't show any of the issues sadly.

 

[raymond.harper]

Most of the chaps swear by the Creator C310 but I have just bought an Ancel BM700 for £70 from eBay, it does both the Z4 and the Mini. A scan yesterday picked up a few issues that the engine management light had not detected. I am sure there will be someone near you with a reader that will be able to help. You can post a separate thread asking if there is anyone near with a scanner

 

[Jas- USA]

Sadly, Faulty ignition switches do not cause codes which can be linked to their fault since they are the correct location for power on/off. They, like a bad battery can cause wild electrical issues from A to Z.

Ignition switches are easy to do and not costly. Hope this helps.

 

[Mike6]

A quick glance at those lights would suggest the abs sensor is dirty or worn and or the reluctor ring needs a clean. Simple and inexpensive Job but can be a right bugger getting the bolt undone

 

[Jack London]

A quick glance at those lights would suggest the abs sensor is dirty or worn and or the reluctor ring needs a clean. Simple and inexpensive Job but can be a right bugger getting the bolt undone

It would, but that wouldn't explain all the electrical gremlins like cutting out the radio and power delivery issues that happens when they do come on.

I just took it for an MOT and they plugged it into their fancy reader and found nothing. Also I changed the battery yesterday but I got the same all lights flash issue once on my drive to the garage.

 

[enuff_zed]

A quick glance at those lights would suggest the abs sensor is dirty or worn and or the reluctor ring needs a clean. Simple and inexpensive Job but can be a right bugger getting the bolt undone

It would, but that wouldn't explain all the electrical gremlins like cutting out the radio and power delivery issues that happens when they do come on.

I just took it for an MOT and they plugged it into their fancy reader and found nothing. Also I changed the battery yesterday but I got the same all lights flash issue once on my drive to the garage.

Ignition switch first then

 

[Jack London]

A little update. The new battery ran for about a day. I sat with the car idling for a while at night when dropping someone off. By the time I was getting home the electrical issues showed up followed by the stereo dying and the screen not coming back on. Car was running a bit rough. By the time I was on my drive the idle was almost stalling. Then all the dash lights and back illumination failed aswell.

Checking the battery my reader said it was almost dead.
Which I guess would suggest the alternator isn't charging.

I ran three tests according to my tester. Headlights on for 3 seconds, then off. Then revs above 2500 and test.
I had the following results:
1. Min voltage: 12.65v Max V: 14.22v. Ripple: 1.56v
2. Min v: 13.97 Max v: 14.13v Ripple: 0.16v
3 Min v: 12.75v Max v: 14.69v Ripple: 1.94v

The following morning the battery has supposedly recovered somewhat and started although not instantly but it's readings were much improved over the previous night without me charging it.

Just seems like such an odd set of problems.

 

[enuff_zed]

You can actually replace the diode/brush pack on the rear of the alternator in situ.
Possibly your next step?

 

[Jack London]

You can actually replace the diode/brush pack on the rear of the alternator in situ.
Possibly your next step?

I'll check that out also. But I'm confused because the readouts suggest the charging is fine right?

 

[enuff_zed]

You can actually replace the diode/brush pack on the rear of the alternator in situ.
Possibly your next step?

I'll check that out also. But I'm confused because the readouts suggest the charging is fine right?

Well it does there, but something is killing the battery?

 

[Jack London]

So I've been thinking about trying to change the voltage regulator on the back of the alternator as I believe is what someone suggested and I've seen similar issues on American forums where this fixed it. Could explain the varied voltage I found when testing charging to the battery. Are there any sites in particular we go for that or parts brands that are recommended?